Helicoidea

Helicoidea is a taxonomic superfamily of air-breathing land snails within the clade Stylommatophora, a group of terrestrial gastropods in the class Gastropoda. The name derives from Helix, the type genus of the Helicidae, one of the major lineages within the group.

Distribution and habitat: Members occur worldwide, particularly in temperate and tropical regions. They occupy a wide range of habitats, from forests and grasslands to gardens, agricultural lands, and urban areas, often in leaf litter, on vegetation, or in rocky substrates.

Taxonomy and composition: Helicoidea comprises several families of terrestrial snails, most notably Helicidae (the typical garden snails), Hygromiidae, Bradybaenidae, and Camaenidae. Other families may be included in the broader circumscription, and the exact composition has shifted with revisions based on molecular data. This reflects ongoing efforts to resolve intragroup relationships among land snails.

Shell morphology and identification: Shells within Helicoidea show substantial variation in size, shape, and sculpture, ranging from globose to elongated forms. Most species have dextral shells, though some lineages may exhibit sinistral coiling. Shells are usually calcareous and may be smooth or ribbed.

Ecology and biology: Helicoid snails are primarily herbivorous or detritivorous, feeding on plant material, fungi, and decaying matter. They are hermaphroditic, with mating typically involving two individuals exchanging sperm. Reproduction and life history vary among families and species.